Traumatic bone injury is often accompanied by injury or loss of surrounding soft tissues. One of the major difficulties reconstructive surgeons face when treating injuries involving significant bone loss is contracture and scarring of the overlying soft tissue envelope, which may compromise facial projection and/or make staged repair of bony structures difficult. Definitive bone reconstruction is often delayed until soft tissue coverage and a sterile wound environment are achieved. Despite reports of local complications and wound infection rates as high as 100% for patients suffering gunshot wounds to the face, early definitive repair of facial gunshot wounds via free tissue transfer has become more common, as the well vascularized tissues that are transferred survive well in hostile wound environments.
The field of regenerative medicine and the technologies borne from tissue engineering offer great hope towards providing an alternative and possibly better approach to regenerating injured or destroyed tissues. Most proposed tissue engineering strategies, however, currently require planning in the form of material fabrication, autologous cell harvest and expansion, and/or ex vivo tissue generation. Additionally, little to no evaluation of tissue engineering approaches is currently performed in wound environments involving infection, significant vascular injury, and large-scale tissue devitalization such as that encountered in traumatic wounds.
In the absence of immediate reconstruction, clinical management of facial bone loss can involve the placement of an alloplastic space maintainer to provide a template for future definitive reconstruction and prevent wound contracture into the space normally occupied by bone. Solid polymethylmethacrylate (PMMA), is commonly used in such space maintenance applications. Although solid PMMA has many desirable characteristics for such applications (moldable, FDA-regulated, familiar to surgeons), a number of problems exist with respect to wound healing around solid PMMA implants and other alloplastic implants.